Advancement of fuel delivery?

[Alky V6]

I found a reference that suggests the following BTUs per pound of mixture at various methanol air fuel ratios.
1,150 at 6.5:1, 1 lambda (14.64 gas readout)
1,200 at 5.2:1, .80 lambda (11.8 gas readout)
1,150 at 4.5:1, .70 lambda (10.2 gas readout)

for comparison:
isooctane (gasoline) 1,210 at 13.2:1
nitro 100% 2,400 at 1.2:1

This states that the btu value of a methanol mixture is highest at a paricular target afr.

I wonder if I were to target an 11.8 target for the als.

Testing of the new 364hp nitrous shot starts today.

 

[TurboTR]

So is all that boost reduction on the 1-2 shift part of your current boost control strategy?

TurboTR

 

[Alky V6]

So is all that boost reduction on the 1-2 shift part of your current boost control strategy?

TurboTR

Was. It's too hard to time the event. I'm going to look into a different strategy.

 

[Alky V6]

I'm sitting in the car waiting for the bottle to get up to pressure. 850, ahh, good enough.

 

[Alky V6]

A short .46 second test.
From 2635 rpm / 95 kPa to 4074 rpm / 101 kPa. That is about 4100 rpm obtained in half the time of the last shot size, with a low bottle pressure.
Looking good.

And the ALS hadn't kicked in yet. :biggrin:

Next test. Longer duration. One second, unless I pee my pants. Same bottle pressure, 850.

 

[Alky V6]

I was able to get more heat into the bottle just before the test. 900 psi.
Timestamp/rpm/map
24.34/2599/95.9 T/C stall just before nitrous activation.
25.14/4353/105.8 Yeah, I know. It's not a full second. I don't have any spare diapers so I didn't want to mess this one up.

ALS in effect for the last .20 sec of the test. The sound was awesome!

RPM had pretty much started to nose over, but map had not.

Mission Successful!!!

 

[Alky V6]

After studying the datalog better, by the shut off of the second nitrous test the RPM was definitely nosing over. The MAP had not leveled out yet. When the ALS became active, the reading shot quickly to 14.64:1. That's typical of what it was doing with the last shot size. I will be adding more fuel to that section of the fuel table. At least enough to where the reading begins to stop shy of the 14.64:1. If the performance keeps increasing, I'll keep adding fuel until the performance levels off.

The exhaust tone takes on a very different sound when the ALS becomes active. It's hard to explain. Rough or ratty is the closest I can come to a description.

I figure I gained about 75% of the shot size increase, judging by how much more TC stall speed was created. 34 out of the 45hp increase. Stall speed increase of around 220 rpm at this point in the tuning in of the new shot size.

 

[Alky V6]

This is the 2nd short test of the new nitrous shot size. This test was done against the transbrake.

It's very apparent that there will be an increase in the 60' performance. Just how much is the question I'm eager to answer. Track testing this weekend.
My guess is the 60' time will drop to around 1.40.

I'll be charging up the batteries for the in car video camera.

 

[Alky V6]

Looking through the tool cabinet and came across this.

 

[Chevota]

I appreciate your posts and experimentation Don. BTW, can I borrow that hydrometer?:biggrin:

 

[Alky V6]

I appreciate your posts and experimentation Don. BTW, can I borrow that hydrometer?:biggrin:

Sorry. It only works with methanol. Does this mean you're switching fuel? You should.

 

[Alky V6]

It's not always a matter of tuning the torque converter to the car. If you're lucky enough to have the right circumstances, and have the right tools at your disposal, you can tune the car to the torque converter.

 

[Alky V6]

I found a reference that suggests the following BTUs per pound of mixture at various methanol air fuel ratios.
1,150 at 6.5:1, 1 lambda (14.64 gas readout)
1,200 at 5.2:1, .80 lambda (11.8 gas readout)
1,150 at 4.5:1, .70 lambda (10.2 gas readout)

for comparison:
isooctane (gasoline) 1,210 at 13.2:1
nitro 100% 2,400 at 1.2:1

This states that the btu value of a methanol mixture is highest at a paricular target afr.

I wonder if I were to target an 11.8 target for the als.

Testing of the new 364hp nitrous shot starts today.

I wonder how this would pertain to systems that use EGT to control the mixture? The temperature peaks at a certain mixture strength, which is already too lean for a blown alcohol application, then begins to drop as the mixture becomes richer. And,... also begins to drop as you go leaner.

 

[Alky V6]

The surface ignition temperature, which is different than the higher self-ignition temperature, for methanol is 1,184 deg. F, compared to that of gasoline which is 1,742 deg. F.
This property shows that methanol is more sensitive to hot spots in the combustion chamber. Carbon build up in a methanol engine is very minimal, but oil that might get past valve seals (or lack of valve seals), or piston rings can contribute to a small amount of carbon buildup that can become a problem for a methanol burning engine.
Carbon buildup in a gasoline engine is a much larger problem and methanol would have a much easier time being ignited by a glowing carbon deposit in the combustion chamber.
Long ground electrodes on spark plugs can easily become a glowing hot spot that could cause surface ignition of methanol.

 

[TARZAN]

The surface ignition temperature, which is different than the higher self-ignition temperature, for methanol is 1,184 deg. F, compared to that of gasoline which is 1,742 deg. F.
This property shows that methanol is more sensitive to hot spots in the combustion chamber. Carbon build up in a methanol engine is very minimal, but oil that might get past valve seals (or lack of valve seals), or piston rings can contribute to a small amount of carbon buildup that can become a problem for a methanol burning engine.
Carbon buildup in a gasoline engine is a much larger problem and methanol would have a much easier time being ignited by a glowing carbon deposit in the combustion chamber.
Long ground electrodes on spark plugs can easily become a glowing hot spot that could cause surface ignition of methanol.

Looking at the roughly 50% difference in surface ignition temp it seems like pre-ignition would be almost inevitable in an engine with some miles on it. Are you still running knock sensors?

-Will

 

[Alky V6]

Looking at the roughly 50% difference in surface ignition temp it seems like pre-ignition would be almost inevitable in an engine with some miles on it. Are you still running knock sensors?

-Will

No. I haven't run knock sensors with this project since the beginning. A knock sensor on a methanol engine is practically useless. If knock is detected on a methanol engine, 9 times out of 10, it's already too late. You'll be sweeping up chunks of rods, pistons and camshaft.
What works better than relying on a knock sensor to tune with, particularly with methanol, is understanding the limits of the fuel and watching ALL the other tuning signs. Unfortunately, unless you have a person who is experienced with burning methanol at your side to help you cut your teeth, you will end up blowing a few motors before better understanding those unique limits. It took me two motors before I gained an adequate respect for this fuel. Actually, I feel very blessed that it only took two. (Feverishly knocking on my wooden desk!!!)
And, as you can see from this thread, I'm still learning about this fuel.

 

[Alky V6]

An interesting study by NASA.

Flame temperature study.

Fuel and condition / Temperature
gasoline in oxygen at stoic / 5,090 deg. F
methanol in oxygen at stoic / 4,742 deg. F
gasoline in air / 3,940 deg. F
methanol in air at stoic / 3,490 deg. F
methanol in air 8:1 CR at 10% lean / 4,562 deg. F
methanol in air 8:1 CR at 10% rich / 4,118 deg. F

Estimated temperature in the arc of a spark plug / 2,400 deg. F

The nitrogen content in the air bufferred the combustion process, controlling flame temperature.

 

[Alky V6]

Looks like the track may be called due to rain for this weekend. Dang it!!! I want to test my shhtuff!!!

 

[Alky V6]

Surface ignition temperature can also be called hot plate ignition. Hydrogen has a lower hot plate ignition limit than methanol. Methanol, as it dissociates, produces a large percentage of hydrogen. This makes hot spots even more of a concern.

 

[Alky V6]

After testing of the new nitrous shot, I came away with a 1.51 60'. A little slower than the last shot size at this point in the tuning. The boost rise after that point is now very steep. I'm having to radically adjust the boost controller pressure curve to tame the boost rise down for the 1-2 shift. I'm also shaving away at the nitrous system shut off point to get the boost rise under control.

After the first two passes on Saturday, I started experiencing intake backfiring just off the launch for three attempts in a row. Didn't do any damage to the motor, but obviously made me a little concerned. I was beginning to regret going with this nitrous shot change.
The intake poppet valve saved me again.
Saturday night I thought about the backfiring and figured that any level of ignition missing would not be a good thing for any nitrous shot size, and I knew the plugs were overdue for a change. Sunday I installed a fresh set of plugs, backed off the time that the nitrous was activated before the transbrake release by .24 second, and the problem disappeared for the rest of the day.

The nitrous is now activated for .75 second before the transbrake releases. I may attempt to bring the .24 second back into the tune for a total of .99 second of nitrous on time before the launch in a future tuning session. What I've noticed is that the more nitrous on time before the launch, the better the 60'.

The main focus now is to get the boost rise curve under control. This was the first weekend that I can remember where the tires blew away after the 2-3 shift.